The production of foods by extrusion is known per se. This applies both to foods for human consumption and to animal feed and fodder.
Thus, it is, for example, known for German Offenlegungsschrift No. 2548285 in connection with the production of starch-containing products to be used as snacks, to feed starch-containing starch products with a residual moisture content of about 10% into a twinscrew extruder, in which there is a gelling process, followed by texturing. There is, however, no addition of flavour-determining ingredients with a high water content, or of water as such.
German Offenlegungsschrift No. 2461453 describes a process for producing dry food from protein-containing and optionally starch-containing raw materials, in which the latter are mixed with water and are extruded forming a product strand or ribbon under elevated temperature and pressure and which, on leaving the screw extruder, spontaneously expands accompanied by the elimination of moisture. As a result, the end product has a porous structure. According to this process, the raw materials are discontinuously premixed, so that the starting product is a raw material mixture having a moisture content of approximately 15% and is fed to the screw arrangement by means of a single supply device. The object is to ensure that the extruded end product does not have to be subsequently dried.